USB 6009 channel mixup

[sankazim]

We are using the NI-DAQmx from C/C++ for recording 8 signals from a USB 6009 board. When the board is powered upthe first recording is successfull, but later recording, also after the reset command give scrambled signals.In particular seems that the signals get reordered always in the same way, and only when the boardis disconnected and powered up again it works correctly, but only for the first recording.Best Regards,Emanuele Ruffaldi

[reikira]

Hi Mr. Ruffaldi,
could you explain me with more details what you mean for "scrambled signals"? How do they get reordered?
Thanks
Serena Monti
Application Engineer National Instruments

[sankazim]

This is what happens:- in the first
acquisition the first channel is very strange (it has something like a
"digital distorsion"), and it contaminates the fifth channel;- in the second acquisition the channels are all "shifted" by four positions (the first is in the fifth place and so on);- the third acquisition is like the first acquisition, the fourth is like the second and so on.Thanks and Best Regards,Emanuele Ruffaldi

[reikira]

You should test your board from the MAX to see if the signals are correct there.&nbsp;If it is so,&nbsp;there is probably a problem with the code you have written: you can have a look at this <a href="http://zone.ni.com/devzone/cda/epd/p/id/583" target="_blank">example</a> and test if you have done something different.
Serena Monti
NI Application Engineer

[sankazim]

We have tested it with MAX and after several tests we have obtained the same problem as with theC++ code: there is a shift between the six signals (#1 is #3, #2 is #4, #3 is #5, #4 is #6, #5 is #1, #6 is #2).When signals are not shifted the acquisition is correct and corresponds to the expectations.Could be a problem of firmware or hardware?Thanks

[reikira]

The hardware problems are usually systematic. If you haven't got the problem in all the tests you have done it sounds more like a problem of software. Since you had the same problem in MAX, there could be something wrong in the configuration of the tasks.
Regards,
Serena

[sankazim]

The MAX task is as follow:- all channels ai0-ai6- 5kHz- Continuos- RSE- Voltage mode- +- 10 VIs there anything else that could generate this kind of effect? Like thefirmware switch between nidaq mx and nidaq mx base?Kind Regards,Emanuele

[reikira]

Are you using DAQmx or DAQmx base?
Are all your channels associated with the same DAQmx Task? In this case you could se how they get ordered with this <a href="http://digital.ni.com/public.nsf/allkb/CC501982F91AFA548625735D00547AC2?OpenDocument" target="_blank">example</a>.
Serena

[sankazim]

We are using DAQmx under MAX, while the display in the provided link is on LABVIEWThanks!

[reikira]

Sorry, I forgot that you are programming in C++.
Could you give me a shot of the MAX test, one for the correct behaviour and one for the wrong one?
What are the "several tests" you did in MAX. Wich worked and wich not?
Thanks

[sankazim]

I have attached the snapshots from MAX:1) configuration of the task2) correct acquisition with the black signal as reference at 1.5VEach input has a microphone attached apart the first (black) that is kept at 1.5V3) shifted acquisition, in which the signals are shifted as previously reportedIt can be noticed looking at the color of the signal used as reference. This time it is blueThank you for supporting us


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a_002.jpg:
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[reikira]

It is&nbsp;very strange. Could you please call me at the technical support?
Thank you
Serena Monti

[sankazim]

Dear Serena,which is the correct number for contacting you?Kind Regards,Emanuele

[reikira]

Emanuele,
After further investigation, I would like to clarify a few more tests before moving forward with a repair. I have run the same test with&nbsp;5 channels using a sinwave on&nbsp;4 of them and a DC output on the 5th. Everything functions correctly and the only time the colors change is when I add or remove a channel. Even though the color changes, the actual value on the channel remains the same. The color is selected in Measurement and Automation Explorer (MAX)&nbsp;by default.
I'm interested to know how you were able to observe a channel swap in MAX? Was it happening during the continuous acquistion or after you restarted the task? I'm interested in trying to reproduce the behavior here so we can get a better understanding.
Here is a screen shot of my test which is similar to yours (missing 1 channel)
&nbsp;


USB 6009.JPG:
http://forums.ni.com/attachments/ni/70/9199/1/USB 6009.JPG

[reikira]

Emanuele,
For phone or email technical support, SSP is required. If you have a valid SSP contract I would be more than happy to troubleshoot over the phone to discuss in real time.
You may also be granted a 30 day trial to evaluate our SSP service and to do so please contact us at 02.41309.217
Thanks,
Serena

[reikira]

&nbsp;
An additional test that you may or may not have tried is to use an external DMM to verify the actual voltage on the channel of question. This will help us determine if the value acquired in MAX is the same as what you read on your DMM.
&nbsp;
Regards,
S.M.

[sankazim]

Dear Serena,the problems was at the level of signals, and indeed we had assigned correctly the colors to thesignals a0-a5. My reference to the colors in the previous post was only done to explain what was shown on the screenshots.Can we contact you at? 02 41309217Kind Regards,Emanuele Ruffaldi